Improvement in key-boards for piano-fortes



y E. C. (JADOT. Keyboard vfor Pan'ofortes.

No.v 215,208.

Patented May I3, 1879.

' diff/1277." /j Q77 UNITED STATES PATENT OFFICEo ETIENNE C. GADOT, OF PARIS, FRANCE.

llVIPROVEMENT lN KEY-BOARDS FOR PIANO-FORTES.

Specification forming part of Letters Patent No. 215,208, dated May 13, 1379; application liled December 2, 1878.

To all whom it may concern.-

Be it known that I, ETIENNE GoNsTANT GADO'r, of Paris, France, have invented new and useful Improvements in Pianos; and I do hereby declare that the following' is a full and exact description thereof.

My invention has for its object the contrivance of an apparatus to which I give the name of galiseur automatique,77 (automatic equalizer,) and which is designed to obviate the imperfections in the play or action of the keys of pianos, whether such imperfections arise from dampness havin caused the wood to swell, thereby preventing the keys from werking, or from the weights inside the keys becoming` oxidized, and therefore too light to cause them to fall down.

My instrument, which may be adapted to pianos of all constructions, renders the play or action of the keys uniform, whatever be the wear or the cause which prevents their free action, the keys readily resuming their normal condition, and not becoming stuck or fixed.

Independently of the advantage obtained by this apparatus as mechanical play, it gives more clearness and more depth to the sound, by increasing the flexibility of the hammers, which rest a shorter time on the strings. It permits the repetition of the notes with greater facility, and, in short, it becomes indispensable to the good working of all pianos.

The annexed drawings illustrate the construction and working of my apparatus.

Figure l is a top view of a piano key-board to which my apparatus is adapted. Fig. 2 is a side section of the same. Fig. 3 shows a front view of the apparatus applied to a keyboard. Fig. is a transverse section of the apparatus on a larger scale, in order to show its construction more clearly.

This apparatus is composed of a wooden bar, a, strengthened at front by a longitudinal right angled brass piece, Z), held to it by screws. A steel plate, c, held behind the bar a by screws, prevents, conjointly with the augle-piece, the bending of the wood.

The wooden bar a has on its under face a number of cavities or recesses, d, equal in number to those of the keys of the key-board, and in each of whichis placed a spiral spring, f. Each of these springs is held to the bottom of the recesses or cavities d by a screw passing through a washer, g, to which it is soldered. Small felt washers interposed between the wood and the washer g prevent jar or vibration.

At the two ends of the bar (c is placed a sliding bolt, 71., the shank of which enters a strap or slotted plate, t', having three slots, j, j, and j', and seen detached at Fig. 5.

The apparatus is placed below the blocks, where it is held by its two bolts 7iy h. Each spring bears against the back of each key, and forces it to rock and rise rapidly.

More or less pressure may be applied to the springs by lowering the bar to the second slot, j, so as to give more strength to the touch, according to the taste and the fingerin g of the pianist.

Vith this arrangement of apparatus, the weights ordinarily placed in the keys may be dispensed with.

Another advantage resulting from my ap paratus is, that it renders the whole keyboard free from jarring, and consequently dispenses with the various small apparatus in use, which now only produce the result on a portion of the keyboard.

To render the key-board thus free for its whole length, the bar must be lowered to the third slot, j', of the staple or slotted plate, which forces the springs to exercise great pressure on the keys, and by raising or drawing back the mechanism or action the keys are then held, although isolated from the mechanism, and they continue to rise up, and the whole length of the key-board can then be played upon without fear of any of the keys getting out of order.

All these combined advantages render my apparatus, as I have before stated, not only indispensable to all pianos working badly, owing to faulty construction, or from dererion ration, but also to all new pianos, to modify the touch and to give to the sound a depth and pureness so diliicult to obtain.

I am aware of United States Patent No.

71,427, and of English Patent No. 2,559 voii' keys of a piano, the bar a., cavities d therein, 1871, and do not wish to be understood as springs f, sliding bolts h, and slotted plate t', claiming anything therein shown or described. substantially as and for the purpose specified. Neither do I claim any ofthe parts, except in In testimony whereof I have signed my the combination hereinafter specified. name to this specification before two subscrib- I claim as my inventioning witnesses. 1. In combination with the key-board and 1 E. Q CADOT.

keys of a piano, the bar a., cavities or springseats d therein, and springs f, substantially as Witnesses:

and for the purpose specified. DAVID T. S. FULLER,

2. In combination with the key-board and ALBERT GAHENT. 

